Hot stamping press



Nov. 19, 1968 J. F. READER ET 3,411,438

HOT STAMPING PRESS Filed Sept. 16, 1966 5 Sheets-Sheet 1 F I6 I 9 N I m m m 5H W 2 4 .I II I III 1 T 40 F E J. 1 I I 1 I 1| m? A mm W J II m ,1 Mu WF x o wm 6 MW 6 1. wm

Nov. 19, 1968 EAD R ET AL 3,411,438

HOT STAMPING PRESS Filed Sept. 16, 1966 5 Sheets-Sheet 2 FIG. 2

! ms Q7 liiiil 170 v 5 Sheets-Sheet J. F. READER ET L HOT STAMPING PRESS .1 I I I Nov. 19, 1968 Filed Sept. 16, 1966 NOV. 19, 1968 J READER ET AL 3,411,438

HOT STAMPING PRES 5 Filed Sept. 16, 1966 5 Sheets Sheet 4 Nov. 19, 1968 READER ET AL Q 3,411,438

HOT STAMPING PRESS Filed Sept. 16, 1966 5 Sheets-Sheet 5 STROKE United States Patent 3,411,438 HOT STAMPING PRESS Julius F. Reader, Park Ridge, and Edwin W. Johnson,

Mount Prospect, Ill., assignors, by mesne assignments,

to United States Steel Corporation, Pittsburgh, Pa., a

corporation of Delaware Filed Sept. 16, 1966, Ser. No. 580,039 9 Claims. (Cl. 101-9) ABSTRACT OF THE DISCLOSURE There is disclosed a hot stamping press for applying indicia to the outer surfaces of the four walls of a substantially rectangular hollow plastic bottle carrying case; the press includes a mandrel for supporting the case and the inner surfaces of the four walls thereof, four heatable dies arranged opposite the four walls of the case and each die carrying thereon raised portions corresponding to the indicia to be applied to the adjacent wall, four feed mechanisms for feeding film carrying a pigment in front of the dies, four drive mechanisms respectively associated with the four dies for moving the dies into and out of engagement with the pigment carrying films and the four walls of the case, and a single drive chain interconnecting the four drive mechanisms for driving the dies in synchronism and to impart simple harmonic motion thereto immediately before, during and after pressing against the associated walls, opposed pairs of dies striking the adjacent walls simultaneously, one pair of opposed dies striking the associated walls shortly after the other. There also is shown mechanism for advancing the pigment carrying film in synchronism with the die drive.

The present invention relates to an improved hot stamping press, and specifically to a hot stamping press for applying indicia to the walls of a plastic bottle carrying case.

Although the hot stamping press of the present invention is of general utility, certain advantages thereof are more fully realized when it is constructed and arranged to apply indicia in the form of pigment to the four sides of a. bottle carrying case of the type disclosed and claimed in US. Patent No. 3,178,052 granted Apr. 13, 1965, to Kenneth W. Bromley for Carrying Cases for Bottles. In the Bromley patent mentioned, there is disclosed a bottle carrying case formed of polyethylene synthetic organic resin including a bottom wall having integral therewith four upstanding side walls, divider walls being disposed integral with and interconnecting the bottom wall and the side walls to form bottle receiving pockets, and an upstanding handle disposed generally centrally of the case and integral therewith and extending upwardly above the four side walls It is highly desirable to apply to at least the upper portions of the four side walls indicia which may include the trademark for the product to be carried therein, the manufacturers name, trade slogans, decorations, and the like. Preferably the indicia are in the form of white pigment applied to and heat sealed onto the outer surfaces of the side walls of the case by a hot stamping press such as that of the present invention.

It is an important object of the present invention to provide a hot stamping press that will apply the desired indicia to the outer surfaces of the side walls of the case, preferably by fusing the pigment onto the surface thereof at an elevated temperature, all without unduly weakening or destroying the side walls of the case, the indicia being applied rapidly with a minimum of labor and cost.

Another object of the invention is to provide an improved hot stamping press of the type set forth comprising a mandrel for supporting the plastic bottle carrying case 3,411,438 Patented Nov. 19, 1968 and the several walls thereof on which the indicia are to be applied, a plurality of heatable dies corresponding in number to the several walls of the case to which the indicia are to be applied, each of the dies carrying thereon raised portions corresponding to the indicia to be applied to the adjacent wall, a drive motor, and drive mechanism positively interconnecting the dies and the drive motor for moving the dies in synchronism between retracted positions wherein the raised portions are spaced away from the adjacent wall and stamping positions wherein the raised portions are disposed near the adjacent wall, whereby when the dies in the heated condition thereof are moved to the stamping positions thereof the raised portions on the dies form patterns on the respectively adjacent walls corresponding to the indicia carried by the respectively associated dies.

In connection with the foregoing object, another object of the invention is to provide a hot stamping press of the type set forth wherein the mandrel is shaped complementary to the inner surfaces of the several walls of the case on which the indicia are to be applied to the outer surfaces thereof, the stamping press including an electric heating element associated with each of the dies to heat the same, all of the dies arriving in the stamping positions thereof simultaneously.

Another object of the invention is to provide an improved hot stamping press of the type set forth wherein the drive mechanism imparts harmonic motion to the dies when the dies are adjacent to the stamping positions thereof to provide zero velocity of the dies at the stamping position-s thereof and maximum deceleration of the dies at the stamping positions thereof.

In connection with the foregoing object, it is another object of the invention to provide an improved hot stamping press of the type set forth wherein the drive mechanism includes guides for the dies to direct the dies along rectilinear paths disposed normal to the adjacent wall, the dies having imparted thereto simple harmonic motion, the preferred drive mechanism being a crank and an associated connecting rod interconnecting the die and the crank arm on the crank shaft.

A further object of the invention is to provide an improved hot stamping press of the type set forth including means for providing between each of the dies and the adjacent wall a film carrying pigment to be transferred therefrom to the adjacent wall, the dies in the stamping positions thereof pressing the raised portions thereon against the adjacent area of the film and to press against the adjacent wall the pigment on the film in patterns correspondirg to the indiia, thereby to adhere the pigment to the adjacent wall in a pattern corresponding to the raised portions onthe die thus to stamp the corresponding indicia on the wall.

In connection with the foregoing object, it is another object of the invention to provide additional drive mechanisms for advancing the films to present fresh pigment surfaces to the dies after movement of the dies out of their stamping positions.

Further features of the invention pertain to the particular arrangement of the parts of the hot stamping press whereby the above-outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings, in which:

FIGURE 1 is a front elevational view with certain parts broken away of a hot stamping press made in accordance with and embodying the principles of the present invention;

FIG. 2 is a rear elevational view of the hot stamping press of FIG. 1;

FIG. 3 is a side elevational view of the hot stamping press of FIG. 1 as viewed from the righthand side thereof, portions of the press having been broken away for clarity;

FIG. 4 is a view in vertical section along the line 44 of FIG. 3 with a portion broken away and illustrating part of the drive mechanism;

FIG. 5 is an enlarged fragmentary view in vertical section along the line 5-5 of FIG. 1, certain portions of the view being diagrammatic to illustrate better the cooperation among the parts;

FIG. 6 is a fragmentary view in vertical section along the line 6-6 of FIG. 5; and

FIG. 7 is a diagrammatic view illustrating the relation- Ship between the movement of the crank arm and the associated die.

Referring particularly to FIGS. 1 to 3 of the drawings, there is illustrated a hot stamping press made in accordance with and embodying the principles of the present invention, the press 100 including a generally rectangular and horizontally disposed base 101 that carries thereon toward the forward edge thereof a vertical up standing frame 102. The frame 102 is also generally rectangular both in front and side elevation and includes an inner frame member 103 (see FIG. 5 also), four side members 104, a pair of top members 105, a front plate 106 and a back plate 107, the back plate 107 being hingedly connected to the frame 102 to provide access to certain parts disposed therein.

Mounted on the frame 102 toward the upper end thereof and centrally thereof in a horizontal direction is a mandrel 110 that is adapted to receive and support a plastic bottle carrying case 120 during the stamping of indicia thereon. The mandrel 110 is generally rectangular as viewed along all three principal axes and is essentially a solid block of steel having a longitudinally extending slot 111 therein and a pair of transversely extending slots 112 therein, the slot 111 being enlarged centrally thereof as at 113, the slots 111 and 112 receiving the divider walls (not shown) on the associated case 120 and the enlarged slot 113 receiving a handle 124 on the case 120 (see FIG. 5 also). Four substantially rectangular side walls 114 are provided around the periphery of the mandrel 110 to rest against the inner surfaces of the four side walls 122 on the associated case 120 (see FIGS. 5 and 6 also), each side wall 114 on the mandrel 110 supporting the associated side wall 122 of the case 120 during the stamping operation. In order to mount the mandrel 110, a rectangular base 115 is provided carrying outwardly directed flanges 116 that are suitably secured as by screws 117 to the inner frame member 103, thereby to support the mandrel 110 thereon, the base 115 having an elongated slot 118 centrally thereof to receive the handle 124 of an associated case. From the above it will be seen that the case 120 can be mounted on the mandrel 110 by inserting the handle 124 thereof in the slot 113 and pushing the case 120 in a horizontal direction and toward the rear of the press 100, thereby fully and firmly to support the case 120 upon the mandrel 110 during the hot stamping of indicia upon the outer surfaces of the side walls 122 of the case 120.

In order to effect the hot stamping operation, four heatable dies are respectively positioned adjacent to the outer surfaces of the four side walls 1220f the case 120 mounted upon the mandrel 110, i.e., adjacent to the four side walls 114 of the mandrel 110 and normally spaced outwardly with respect thereto and with respect to the side walls 122 of the case 120. Referring particularly to FIGS. 5 and 6 of the drawings, it will be seen that each of the dies 130 is essentially rectangular in configuration and carries on the face thereof disposed toward the associated side wall 114 of the mandrel 110 raised portions 131 in the form of indicia to be stamped upon the adjacent side wall 122 of the case 120 mounted on the mandrel 110, The die 130 is more particularly mounted on a base 132 having attached thereto slides or gibs 133 which are mounted by guides 134 to accommodate movement of the die 130 toward and away from the mandrel 110, such movement of the die 130 being along a rectilinear path and substantially normal to the associated side wall 114 of the mandrel 110. In order to heat the die 130 to the necessary operating temperature thereof, there are imbedded therein heating elements 135 that are electrically energized, a meter 136 being provided adjacent to the upper edge of the front plate 106 for each of the four dies 130, see FIG. 1, the dies normally being heated in the range from about 200 F. to about 300 F.

In order to move each die 130 toward and away from the mandrel 110, a drive motor 140 has been provided on the frame 102 (see FIGS. 1 and 3) the drive motor 140 being disposed within a housing 141 carried on the base 101 and to the rear of the frame 102, the housing 141 being essentially rectangular in shape and provided with a pair of doors 142 permitting access to the motor 140 and the other components disposed within the housing 141. The output of the motor 140 is connected by means of a clutch 143 to the input of a speed reducer 144, the clutch 143 and the speed reducer 144 both being disposed in the frame 102. The speed reducer 144 is provided with an output shaft 145 (see FIG. 4 also) that carries thereon a sprocket 146 to be driven thereby, the sprocket 146 engaging a drive chain 147 of the continuous and endless type, a sprocket 148 also being provided in engagement with the drive chain 147 to adjust the length thereof.

Interconnecting the drive chain 147 and each of the dies 130 is a drive mechanism 150, four drive mechanisms 150 being provided so that each of the four dies 130 has its own drive mechanism 150. The drive mechanisms 150 are of a type which convert rotary motion to rectilinear simple lharmonic motion, thereby to impart to each of the dies 130 simple harmonic motion of a reciprocating character along a rectilinear path. Each of the drive mechanisms 150 includes a sprocket 151 having teeth thereon engaging the drive chain 147, whereby all of the drive mechanisms 150 are driven in unison by the drive chain 147. Referring to FIGS. 5 and 6, the top drive mechanism 150 for the top die 130 and will be described in detail, it 'being noted that the sprocket 151 is fixedly mounted on the outer end of a crank shaft 152 that is supported by a first bearing 153 on the inner frame member 103 and a bearing 154 on the front plate 106, the crank shaft 152 being mounted for free rotation. Disposed between the bearings 153-154 is a crank arm 155 integral with the crank shaft 152 and having provided thereon a bearing sleeve 156.

Interconnecting the crank arm 155 and the topmost die 130 is a connecting rod 160, the connecting rod carrying at the upper end thereof a hub 161 receiving the bearing sleeve 156 therein and having integral there with both an elongated ram 162 and a yoke 163. The outer end of the ram 162 has a threaded opening therein and the outer central portion of the yoke 163 has a threaded opening therein in alignment with the threaded opening in the ram 162, the aligned threaded openings receiving an externally threaded arm 165 therein carrying two positioning nuts 166. The outer end of the arm 165 carries a ball pivot 167 that is received in a cage 168 mounted on the rear of the die base 132 and fixedly connected thereto. The nuts 166 are threadedly movable along the arm 165 so as to position the ball joint 167 at any desired adjusted position away from the crank arm 155, thereby elfectively to adjust the length of the connecting rod 160. It will be understood that the crank 155 acting through the connecting rod 160' will reciprocate the die 130 along a rectilinear path determined by the guides 134, the distance of reciprocation of the die 130 being equal to twice the throw of the crank 155 and the inner and outer positions of the die 130 being predetermined by theadjustment of the arm 165 with respect to the crank 155 and the die 130. The described c0nstruction serves to impart simple harmonic motion to the die 130 as it is reciprocated along a rectilinear path, the rotary motion of the crank arm 155 being converted to rectilinear simple harmonic motion as is diagrammatically illustrated in FIG. 7. In such harmonic motion of the die 130, the die 130 has essentially zero velocity at the solid line position illustrated in FIG. 7 and maximum deceleration at the solid line position illustrated in FIG. 7, the velocity and acceleration being sinusoidal when the parts move between the solid line position and the dashed line position of the die 130 in FIG. 7.

In accordance with the present invention, it further is desirable to provide a film 170 carrying a pigment on at least one surface thereof, the pigment preferably being white, the film 170 being disposed between the heated die 130 and the associated side wall 122 of the case 120 so that when the die 130 is moved into the stamping position, the pigment carried by the film 170 is disposed toward the adjacent side wall 122 and is transferred thereto and imbedded therein in accordance with the indicia provided by the raised portion 131 on the die 130. After a hot stamping operation, a new pigment surface of the film 170 is then presented to the die 130 so as to ensure a full supply of pigment for the next hot stamping operation. Preferably four of the films 170 are provided, one for each of the dies 130.

Referring particularly to FIGS. 1, 2 and 5, the structure for supplying and moving the films 170 will be described in detail, such structure for the film 170 associated with the topmost die 130 being described for illustrative purposes. A supply reel 171 for the film 170 is provided, the supply reel 171 being mounted by a bracket 172 on the front plate 106 above the die 130 and in substantial longitudinal alignment therewith. Carried on the die base 132 is a pair of guide rolls 173 respectively mounted by arms 174, the guide rolls 173 being mounted on opposite sides of the die 130 to hold a section of the film 170 in overlying relationship with respect to the raised portions 131 on the die 130, whereby to position the aforementioned section of the film 170 between the raised portions 131 of the die 130 and the adjacent side wall 122 of the case 120. After a stamping operation, it is necessary and desirable to present a fresh section of the roll 170 to the raised portions 131 on the die 130, and to this end a drive motor 175 has been provided for the film 170, it being pointed out that a separate drive motor 175 is provided for each of the separate four films 170. The output of the drive motor 175 is connected as the input to a drive box 185 and the output of the drive 'box 185 is con nected to a shaft 176 journaled in a bracket 177 mounted on the back plate 107. The shaft 176 carries a drive roll 178 which is driven thereby and over which is fed the film 170, a guide roll 179 being provided between the adjacent guide roll 173 and the drive roll 178. The tape from the drive roll 178 is wound upon a take-up reel 180 mounted by means of a bracket 181 on the back plate 107, a belt 182 interconnecting the drive shaft 176 and the take-up reel 180 so that the take-up reel 180 is driven thereby. A squeeze roll 183 is also provided adjacent to the drive roll 178 to ensure a smooth and proper feeding of the film 170 thereby.

It will be seen that the movement of the die 130 into operative contact with the case 120, and more specifically the movement of the raised portions 131 toward the adjacent side wall 122, will carry the adjacent section of the tape 170 into contact with the adjacent side wall 122, the pigmented surface of the film 170 being disposed toward the adjacent side wall 122. The die 130 is heated as noted above and in the heated condition can soften the synthetic organic plastic resin,- such as polyethylene resin, of which the case 120 is formed, and also presses the adjacent section of the film 170 against its associated side wall 122. Only the raised portions 131 on the die 130 are brought into contact with the film 170 and the heat from the die 130 is conducted through the raised portions 131 her 103. The upper end of the shaft and the film 170 to heat the material of the adjacent side wall 122, pigment from the tape 170 also being transferred onto and into the softened or melted material of the adjacent side wall 122. Only the area of the side wall 122 corresponding to the raised portions 131 will be heated and will have pigment from the film 170 deposited thereon and fused thereinto. It will be appreciated that the die 130 must be pressed firmly against the side wall 122 but must not be pressed too hard if the structural integrity of the wall 122 is to be preserved. Accordingly, the adjustment provided by the threaded arm 165 and the nuts 166 is made so that only a shallow indentation is made in the side wall 122 by the heated raised portions 131.

It has been found that the simple harmonic motion imparted to the dies 130 by the drive mechanisms 150 is very beneficial in providing a proper amount and proper character of contact of the heated dies 130 through the films 170 with the associated side walls 122. It further has been found highly advantageous to move the two dies in an opposed pair of the dies 130 into the stamping positions thereof simultaneously so that the stamping pressures are applied uniformly to the opposite sides of the mandrel and the case mounted thereon, one pair of opposed dies moving into the stamping position shortly after the other. The positive drive from the motor through the drive chain 147, the sprocket 14S and the drive mechanisms ensures that all four of the heated dies 130 reach the inwardmost positions thereof simultaneously, the dies 130 being moved in unison and in synchronism by the described drive train. The drive mechanisms 150 impart simple harmonic motion to the dies 130 when moving between the retracted and stamping positions thereof, thus to effect the highly desirable character of contact between the dies 130 and the side walls 122 through the films described above. After the dies 130 are moved from the stamping positions thereof toward the retracted positions thereof, the motors are automatically energized to advance the associated films 170 a distance sufiicient to present a fresh film section and an associated fresh pigment surface to the opposite ralsed portions 131 of the associated die 130, the fresh film being supplied from the supply reel 171 and the used film being wound upon the take-up reel via the drive reel 178 and the drive belt 182.

After the indicia have been hot stamped upon the side walls 122 of the case 120, it is desirable automatically to eject the case 120 from the mandrel 110 and to this end a knockout mechanism has been provided. Referring to FIGS. 2, 4 and 5 of the drawings, it will be seen that the sprocket 151 disposed to the left in FIG. 4 has associated therewith a cam 191 which is driven in synohronism therewith from the drive motor 140, the cam 191 cooperating with a crescent shaped arm 192 pivoted at one end as at 193 and carrying thereon a roller 194 in contact with the cam 191. The other end of the arm 192 has a slot 195 therein receiving a pin 196 attached to a rack 197, the rack 197 being supported in a pair of guides 198. The arm 192 is held in a position toward the cam 191 to place the roller 194 continually in contact therewith, and to this end a bracket 199 is provided on the rack 197 and has connected thereto one end of a coiled spring 200, the other end of the spring 200 being secured to the inner frame member 103, the spring 200 serving to urge the rack 197 to the left as viewed in FIG. 4 and thus to pivot the arm 192 in a clockwise direction and thus to urge the roller 194 into contact with the cam 191. The rack 197 carries the usual teeth on the outer end thereof that are engaged by a pinion 201 supported on the lower end of a shaft 202, the shaft 202 being rotatably mounted with respect to the inner frame mem- 202 carries a second pinion 203 which engages the teeth on a knockout rack 204, the rack 204 being supported by guides 205 for movement in a direction normal to the inner frame memher 103. Referring to FIG. it will be seen that the inner end of the rack 204 extends into the slot 118 in the mandrel base 115 and in alignment with the handle 124 of the case 120 mounted on the mandrel 110. Inward movement of the rack 204, i.e., movement to the left as viewed in FIG. 5, will place the rack 204 in contact with the handle 124 and further movement of the rack 204 to the left will serve to push the case 120 from the mandrel 110. The necessary motion of the rack 204 is derived from the cam 191 and is transmitted thereto via the roller 194, the crescent shaped arm 192, the pin 196, the rack 197, the pinion 201, the shaft 202 and the pinion 203. The parts in FIGS. 4 and 5 are shown with the rack 204 in the retracted position. Movement of the pin 196 to the dashed line position in FIG. 4 will cause the rack 197 to move to the left thus to rotate the pinions 201 and 203 in a counterclockwise direction as viewed from the top and will move the rack 204 inwardly or to the left as viewed in FIG. 5. From the above described connection, it will be seen that the knockout mechanism 190 will be automatically operated at a predetermined point in the cycle of operation due to the fact that the control cam 191 is driven by the main drive motor 140 through the main drive chain 147.

Preferably the hot stamping press 100 is essentially automatic in operation and to this end a guard rail 109 is provided on the front and carries a pair of operating buttons 210 and 211, see FIGS. 1 and 3. A plurality of control switches 212, 213 and 214 are operated by a cam 215 driven with the sprocket 151 disposed to the right as viewed in FIG, 4, whereby the main drive chain 147 controls the operation thereof, the switches 212, 213 and 214 being incorporated in a conventional control circuit and being operated in predetermined time sequence with respect to all other operations of the press 100 to effect the proper sequential operation of the parts of the press 100 in the order and manner described above. There further is provided on the front plate 106 a control panel 216 carrying a plurality of push button controls for energizing the 'various motors and heaters.

In the operation of the hot stamping press 100, the operator first ascertains that a suitable supply of film 170 is present on each of the supply rolls 171 and that each of the films 170 passes across the raised portions 131 of the associated die 130 and over the drive roll 178 and up onto the take-up reel 180. Suitable electrical connections are then made to the heating elements 135, the motor 140 and the motors 175. A case 120 is then placed upon the mandrel 110 in the position illustrated in FIGS.

1, 5 and 6. The operator presses the operating buttons 1 210 and 211 to cause the intiation of a cycle of operation. The motor 140 at this time is connected via the clutch 143 and the speed reducer 144 to the drive chain 147 to cause movement thereof at a predetermined rate. The drive chain 147 in turn positively drivers simultaneously and in synchronism the four drive mechanisms 150 associated respectively with the four heatable dies 130. The drive mechanisms 150 convert the movement of the main drive chain 147 to rectilinear simple harmonic motion of the heated dies 130 toward the adjacent section of the films 170 and toward the associated side walls 122 of the case 120. The heated raised portions 131 are brought into contact with the films 170 and press the pigment on the other side thereof into contact with the outer surface of the adjacent side walls 122, and the portions of the side walls 122 opposite the heated raised portions 131 are softened whereby to receive indentations therein corresponding to the indicia formed by the raised portions 131 and also to receive from the films 170 pigment areas corresponding to the raised portions 131, the pigment not only being transferred from the film 170 onto the side walls 122, but also being fused onto the softened and melted surfaces of the side walls 122. -In accordance with the present invention, the simple harmonic motion imparted to the dies 130 provides for optimum contact with the films 170 and optimum pressure against the adjacent side walls 122 and an optimum duration of contact therewith. It also is important that all four dies 130 move to the stamping positions thereof in synchronism and that both dies in an opposing pair of the dies 130 reach the stamping position simultaneously, one pair of opposed dies moving into the stamping position shortly after the other, thereby to balance the forces applied of the mandrel and the case supported thereon.

As the dies are moved from the stamping positions thereof toward the retracted positions thereof, the motors 175 are energized by the control circuit outlined above, thereby automatically to advance the film after a predetermined advancement of the films 170 so as to provide a fresh section opposite the raised portion 131 on the associated die 130 and thus to prevent a fresh pigment surface thereto, the motors are de-energized. It will be understood that the used films 170 are wound upon the associated take-up reels during the film advancement operation.

Also during the time that the dies 130 are moving from the stamping positions thereof toward the retracted positions thereof, the knockout mechanism is operated from the drive chain 147 to remove the case 120 from the supporting mandrel 110*. After these operations, the control mechanism automatically decouples the drive chain 147 from the motor 140 until such time as the operating buttons 210 and 211 are again actuated. It will be understood that at this time the operator would insert a new case 120 onto the mandrel 110 for the next hot stamping operation.

From the above it will be seen that there has been provided an improved hot stamping press which fulfills all of the objects and advantages set forth above. While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A hot stamping press for applying indicia to the outer surfaces of the four walls of a substantially rectangular hollow plastic bottle carrying case; said press comprising a mandrel supporting the case and the inner surfaces of the four walls thereof, four dies arranged adjacent to the outer surfaces of the four walls of the case and each die carrying thereon raised portions corresponding to the indicia to be applied to the adjacent walls, each of said dies being mounted for movement between a retracted position wherein said raised portions are spaced away from the adjacent wall and stamping positions wherein said raised portions are pressed toward the adjacent wall, means for heating said dies, a drive motor, and drive mechanism positively interconnecting all four of said dies and said drive motor for moving said dies in syncluonism between said retracted positions and said stamping positions, said drive mechanism imparting harmonic motion to said dies as said dies approach and are retracted from the stamping positions thereof to provide zero velocity of said dies at the stamping positions thereof and maximum deceleration of said dies at the stamping positions thereof, opposed pairs of said dies moving into the stamping positions thereof simultaneously so that the stamping pressures therefrom are applied uniformly to the opposite sides of said mandrel and the case mounted thereon, whereby when said dies in the heated condition thereof are moved to the stamping positions thereof indicia corresponding to the raised portions on said dies are applied to the walls.

2. The hot stamping press set forth in claim 1, wherein said mandrel is shaped complementary to the inner surfaces of the four walls of the case on which the indicia are to be applied on the outer surfaces thereof.

3. The hot stamping press set forth in claim 1, wherein one pair of opposed dies moves into the stamping positions thereof shortly after the other pair of opposed dies moves into the stamping positions thereof.

4. The hot stamping press set forth in claim 1, where- I in said drive mechanism directs said dies along rectilinear paths disposed substantially normal to the adjacent wall.

5. The hot stamping press set forth in claim 1, wherein said drive mechanism imparts simple harmonic motion to said dies in moving between the retracted positions and the stamping positions thereof.

6. A hot stamping press for applying indicia to the outer surfaces of the four walls of a substantially rectangular hollow plastic bottle carrying case; said press comprising a mandrel supporting the case and the inner surfaces of the four walls thereof, four dies arranged adjacent to the outer surfaces of the four walls of the case and each die carrying thereon raised portions corresponding to the indicia to be applied to the adjacent walls, each of said dies being mounted for rectilinear movement between a retracted position wherein said raised portions are spaced away from the adjacent wall and stamping positions wherein said raised portions are pressed toward the adjacent wall, means for heating said dies, a drive motor, a drive mechanism for each of said dies including a crank shaft mounted for rotation about the longitudinal axis thereof and having a crank arm, a connecting rod interconnecting the crank arm and the associated dies, a drive chain positively interconnecting said drive motor and all four of said crank shafts for driving said dies in synchronism, said drive mechanisms each imparting simple harmonic motion to the associated die as the die approaches and is retracted from the stamping position thereof to provide zero velocity of the die at the stamping position thereof and maximum deceleration of the die at the stamping position thereof, opposed pairs of said dies moving into the stamping positions thereof simultaneously so that the stamping pressures therefrom are applied uniformly to the opposite sides of said mandrel and the case mounted thereon, whereby when said dies in the heated condition thereof are moved to the stamping positions thereof indicia corresponding to the raised portions on said dies are applied to the walls.

7. The hot stamping press set forth in claim 6, wherein one pair of opposed dies moves into the stamping positions thereof shortly after the other pair of opposed dies moves into the stamping positions thereof.

-8. A hot stamping press for applying indicia to the outer surfaces of the four walls of a substantially rectangularhollow plastic bottle carrying case; said press comprising a mandrel supporting the case and the inner surfaces of the four walls thereof, four dies arranged adjacent to the outer surfaces of the four walls of the case and each die carrying thereon raised portions corresponding to the indicia to be applied to the adjacent walls, each of said dies being mounted for movement between a retracted position wherein said raised portions are spaced away from the adjacent wall and stamping positions wherein said raised portions are pressed toward the adjacent wall, means for heating said dies, four feed mechanisms mounted respectively adjacent to said dies for feeding a film carrying a pigment to be transferred therefrom to the adjacent wall, a drive motor, and drive mechanism positively interconnecting all four of said dies and said drive motor for moving said dies in synchronism between said retracted positions and said stamp ing positions, said drive mechanism imparting harmonic motion to said dies as said dies approach and are retracted from the stamping positions thereof to provide Zero velocity of said dies at the stamping positions thereof and maximum deceleration of said dies at the stamping positions thereof, said raised portions in the stamping positions of said dies pressing the associated films and the pigment thereon at the areas corresponding to said raised portions against the adjacent walls, opposed pairs of said dies moving into the stamping positions thereof simultaneously so that the stamping pressures therefrom are applied uniformly to the opposite sides of said mandrel and the case mounted thereon, whereby when said dies in the heated condition thereof are moved to the stamping positions thereof the pigment on the films in the areas corresponding to said raised portions on said dies is pressed against the respectively adjacent walls and the pigment adhered thereto in patterns respectively corresponding to said raised portions thus to apply the respectively corresponding indicia to the walls. 9. The hot stamping press set forth in claim 8, and further comprising additional drive mechanism operativcly connected to said films for advancing the same to present fresh pigment surfaces to said dies after movements of said dies out of their stamping positions.

References Cited UNITED STATES PATENTS 2,505,900 5/1950 Knitter 10l41 2,860,572 11/ 1958 Prohaska l0l--4l 3,180,253 3/1965 Hild-mann l01--4'l 3,282,201 11/1966 Sobran 101-9 2,132,981 10/1938 Avery l0l-3l6 ROBERT E. PULFREY, Primary Examiner.

H. DlN-ITZ, Assistant Examiner. 

